Primer pushed in after firing ???

[BookemDano]

I'm stumped by what happened yesterday.

2nd round of testing Hornady 75 grain hpbt match bullet with TAC powder.
5.56 with 2.25 col, cci standard primer.
Western Powder lists the max load at 25.8 grains.

I did initial testing last week with 23.8 - 25.3 grains of powder.
I decided to just test 24.6 and 24.7 yesterday.
Primers flattened, not excessive, with minimal cratering.
weighted each load individually & hand primed each.
2825 average velocity w/ 24.7 grains, then this one shot hit 2908 fps and the primer appears pushed in, instead of flushed out to case head.
It was not pierced.

Never seen anything like this before. Anyone have a clue?

 

[Old_Me]

I'm stumped by what happened yesterday.

2nd round of testing Hornady 75 grain hpbt match bullet with TAC powder.
5.56 with 2.25 col, cci standard primer.
Western Powder lists the max load at 25.8 grains.

I did initial testing last week with 23.8 - 25.3 grains of powder.
I decided to just test 24.6 and 24.7 yesterday.
Primers flattened, not excessive, with minimal cratering.
weighted each load individually & hand primed each.
2825 average velocity w/ 24.7 grains, then this one shot hit 2908 fps and the primer appears pushed in, instead of flushed out to case head.
It was not pierced.

Never seen anything like this before. Anyone have a clue?

i have only been reloading maybe now about 4 years this month (October???)

pistols only and always "under max charges"

so no, in my limited time/experience, i have not seen that before.

 

[powerboatr]

i only do my pistol rounds, but if the case was over pressurized... wouldn't it be bulged out vice depressed inward?
did the primer seat fully into the brass? thats about alll i got sorry

 

[BookemDano]

... wouldn't it be bulged out vice depressed inward?
did the primer seat fully into the brass?

Exactly my dilemma. The inward push is what's so odd.
Maybe it pierced and back pressure reshaped it, I dont know
Primers were all hand seated & thumb checked when loaded.

 

[Recusant]

I know this can happen when firing vintage military rifles. Read that this happened because original military ammo had “harder” primers that allowed the ammo to fire after long time storage. So since we are brainstorming, perhaps your primers are softer than what’s being used on standard factory ammo. I had this problem when firing my Type 38 Japanese rifles. The primers they used were “harder” than today’s factory ammo.

 

[Belt Fed]

I had a 7.62x39 steel case do that the other day. it didn't fire.

 

[TEXASforLIFE]

Exactly my dilemma. The inward push is what's so odd.
Maybe it pierced and back pressure reshaped it, I dont know
Primers were all hand seated & thumb checked when loaded.

What brass is that? How deep were/are the pockets? more questions later

 

[TEXASforLIFE]

which firearm

 

[MN300PRC]

Pistol primers in a rifle case?

 

[Jester560]

Pistol primers in a rifle case?

That's my guess

 

[TEXASforLIFE]

Pistol primers in a rifle case?

That's my guess

he stated cci standard as that should be 400's and not 500's

 

[MN300PRC]

he stated cci standard as that should be 400's and not 500's

Arnt 400 and 500 both standard but for srp and lrp?

 

[BookemDano]

...Ruger American scout gen2, CCI 400 RIFLE primers, PMC M855 brass. Second reload, nice tight primer pockets, swaged before 1st reload & seated to just below flush by hand tool.
I've reloaded over 500 rounds with same brass & same pack of primers, never a problem.

 

[835mag]

Looks like you may have given that case a second hit with the firing pin.

 

[TEXASforLIFE]

Arnt 400 and 500 both standard but for srp and lrp?

They are